Semiconductor devices, such as transistors and polysilicon-based resistors, use various insulating materials to conductively isolate portions of these devices. For example, polysilicon resistors are often formed on insulating layers to prevent conduction and mitigate other electrical activity with components on the other side of the insulating layers. An example is polysilicon resistors formed in shallow trench isolation (STI) devices. In STI, an epitaxial layer is formed on a substrate. The epitaxial layer is selectively etched to form shallow trenches that are subsequently filled with an insulator, such as silicon dioxide, that may be deposited using chemical vapor deposition techniques. Under ideal conditions, these silicon dioxide layers provide very good insulation. However, conditions are sometimes not ideal. When etching the shallow trench, particles from various sources can settle in unwanted places. Despite sophisticated cleaning procedures, these particles may not be completely removed. During the shallow trench etching process, these particles may block the etchant and leave a cone of epitaxial material. This creates a thin spot in the subsequently deposited insulator. In addition, these thin spots typically cannot be detected using test screens for functionality because the device performs as designed until a large electric field occurs at the thin spot, breaking through the insulation. Thus, the device may pass testing, but fail in use. Thus, there is a need for a device design that reduces the risk of failure of the insulator between the cone and an overlying circuit.